Mediterranean green roofs: selecting for proper plant species and soil type

Recent studies have highlighted the ecological, economical and social benefits of green roof technology to urban areas. Green roofs are potential hostile environments for plant growth because of limited water availability. For this reason, this technology is still uncommon in hot and arid regions like Mediterranean countries. Moreover, relatively few studies have explored the possibility to use plant species alternative to the traditional Sedum sp. for development of green roof modules, despite the floristic richness (and drought adaptation) of native species in Mediterranean biomes. This study provides experimental evidences for the possibility to use two Mediterranean native species (i.e. Arbutus unedo L., arbutus and Salvia officinalis L., sage) in green roof systems. Our data show that both arbutus and sage plants face environmental stresses imposed by green roof technology with success. However, much attention must be paid to soil type and an irrigation system seems to be advisable, especially for S. officinalis plants.